Refrigerating apparatus



June 23, 1936. E. B. NEWILL REFRIGERATING APPARATUS 2 Sheets-Sheet 2Filed July 31, 1934 r vu xp/ /d /u /d\ a PatentedqJ une 2 3,; 1936PATENT OFFICE asramm'rma mmrus Edward B. Newlll. Dayton, Ohio, auignorto Gena J oral Motors Corporation, Dayton, Ohio, a cornotation ofDelaware Application July 31, 1934, No. 787,787

8 Claims.

This invention relates to refrigerating apparatus and particularly toevaporators or cooling elements thereof.

Refrigerating apparatuses or systems of the 6 present-day type usuallyhave two major features embodied therein. The first of these features isthe provision of an evaporator am. a refrigerant flow circuittherethrough which will produce rapid freezing of substances placed intrays or receptacles and positioned on or in an evaporator while at'thesame time coolingthe air within a refrigerator cabinet to the propertemperature for food preservation. The second of these major features isthe provision of some sort of means for causing semi-automatic orantomatic defrosting of the evaporator or in other words to cause atemporary higher temperature of the air cooling walls of the evaporatorfor melting frost orice accumulated thereon therein extensivedevelopment of evaporators of special or unique design for refrigeratingsystems and the invention herein disclosed is an improvement in the artof evaporator design constructed especially to carry out the desirablefeatures of a refrigerating system without loss of efliciency.

An object of the invention is to provide an evaporator or coolingelement having an arrangement of passages therein which will permiteffective circulation of refrigerant in the evaporator so as to'. coolcertain surfaces thereof as desired and to provide an evaporator whichcan be readily fabricated from sheet metal shells or plates.

Another object of the invention is to provide an-improved evaporator ofthe type having a pluralityof walls forming an air cooling portion forthe evaporator and a chamber therebetween adapted to receive receptaclescontaining substances tobe congealed or. frozen, within the chamber andto construct and arrange the shelves in such mannerthat a difference inthe temperature of the air cooling portion or walls of the 4 evaporatorrelative to the temperature of the shelves will not materially affectthe normal low temperature of the shelves.

In carrying out the foregoing object it is still a further objectto'provide temperature 'hold-over means in thermal contact with arefrigerated shelf within a freezing chamber or compartment defined bywalls of an evaporator for maintaining the temperature of the shelfsubstantially constant during a temporary increase in the tem- 55perature of the evaporator walls.

from. These two desirable features have resulted with a refrigeratedsharp freezing shelf or shelves,

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings, wherein a preferred form of the. present invention is clearlyshown.

, In the drawirigsz- Fig, 1 discloses a refrigerator cabinet ofthehousehold type having an evaporator constructed according to 'thepresent invention installed. therein;

Fig. 2 Ban enlarged side ,eiev'ational view of my-improved evaporator;

Fig. 3 is an enlarged vertical sectional view of my improved evaporatortaken on the line 3--3 of Fig.2 and showingthe chamber formed by theevaporator walls as being divided into a plurality of compartments byrefrigerated shelves; and- Fig. 4 is a sectional view taken on the line44 of Fig. 3 showing the bottom of one of the refrlgerated shelves. I

Referring to the drawings, for the purpose of illustrating the presentinvention, I have shown in Fig. 1 thereof an evaporator constructedaccording to my invention mounted in the refrigerator cabinet 2 i of anysuitable construction or design. Preferably the cabinet 2| comprises aninsulated food storage compartment 22 having a door 23'providing accessthereto and a machine compartment (not shown) disposed below the foodcompartment. The refrigerant liquefying and circulating unit or machineof the re-.

' frigerating system, connected with the evaporator 20, may be of anysuitable type. and is adapted to be mounted in the machine compartment.Mechanical refrigerant liquefying and circulating 35 units or machinesof type mentioned are well known to those familiar with the art and needno detailed description.

The evaporator 20 is produced by uniting in any suitable mannersuperimposed sheet metal plates or telescoped sheet metal shells 25 and-26 (see Fig. 3) to provide a double walled structure having passagesformed between the plates or shelves. The united plates or shells 25 and26 are arranged to form a top wall 21, a bottom wall 28 and side walls29 and 30 of an elongated horizontally extending freezing chamber orcompartment. A liquid refrigerant inlet connection 32 and a gaseousrefrigerant outlet connection 33 are connected with the evaporator 20.The refrigerant connection 32 may be-connected with a refrigerantcontrol device (not shown) of any well known type for governing orcontrolling the flow of liquid refrigerant to the evaporator. Therefrigerant flow control device may be in the I by these walls bymembers 51.

form of a restriction expansion or float valve. The refrigerantconnection 33 leads from the evaporator 20 to the crankcase or suctionside ofa compressor, ordinarily included as an element of therefrigerant liquefying and circulating unit, for withdrawing gaseousrefrigerant from the evaporator, In order to provide the evaporator witha fast freezing portion and a relatively warmer portion for cooling airthe refrigerant connection 32 leads to a serpentine refrigerant conduit35 formed in the shelf 33. A

pipe 31 conducts refrigerant from the conduit 35, in shelf 36, to aconduit 33 formed in a shelf 33. The shelves 36 and 39 provide theevaporator with fast freezing supports adapted to receive receptacles 40containing a substance to be congealed'or frozen. The shelves 36 and 39divide the chamber or compartment, formed by the walls 21, 26, 29 and 30of the evaporator, into a plurality of superimposed compartments.Shelves 55 and 39 each include superimposed sheet metal portions ormembers 4| and if: (see Fig. 3) secured together in any suitable manner.The refrigerant conduits 35 and 38 provided in shelves t6 and 39 extendhorizontally through the chamber or compartment formed by walls of theevaporator and are formed by depressions provided in the lower sheetmetal portion 42 of the shelves. A pipe 43 conducts refrigerant from theconduit 38, in shelf 39, to a header or distributing manifold 65 formedby and located between the sheet metal plates or shells 25 and 23 in thebottom wall, 28 of the evaporator. A plurality of refrigerant passages46 formed by and located between the sheet metal plates or shells 2!:and 26 extend outwardly from each side of' the manifold 45 and upwardlyalong the walls 28 and 33 and along the top wall 21 and communicate witha gaseous refrigerant outlet header or chamber 41 to which the gaseousrefrigerant return pipe 33 is connected.

It will thus be seen that I have provided a refrigerant flow circuitthrough the sheet metal evaporator 20, between the refrigerant inlet andoutlet connections thereof, which includes an extended portioncomprising the shelves 33 and 33 connected in series with the inletconnection 32 and which portion is capable of producing very lowtemperatures and another portion connected in parallel circuit relationwith the outlet connection 33 to provide refrigerated wall portionswhich are maintained at a higher temperature than the shelves forcooling and causing circulation of air within the food storagecompartment 22 of cabinet 2|.

The refrigerated shelves 33 and 33 have the major portion thereof spacedfrom the side walls 29 and 30 of the evaporator and are supported Themembers 3| may be of any suitable material, preferably of a material oflow heat conductivity and being separate from and independent of thematerial of the-evaporator walls and of the shelves 33 and 33. Members5| are secured to the shelves 33 and 33 and to the side walls 29 and 33in any suitable manner. The feature of supporting the shelves 36 and 39as disclosed will become'apparent from the folllowing description of thepresent invention. Each refrigerated shelf includes a sheet metalportion 52 having the portion thereof adJacent its edges secured in anysuitable manner to the lower sheet metal portion 42 of the shelves. Theportions of the sheet metal member 52 intermediate its secu'redportionsis bulged outwardly so as to be spaced from the frigerator cabinet.

metal shelf portion 42 to provide a sealed chamber 53 along the bottomof the shelves. A nonfreezing solution such as brine or the like isadapted to be placed in and sealed within the chamber 53.

The refrigerant flowcircuit through the evaporator as hereinbeforedescribed provides a portion adjacent the refrigerant inlet which ismain-' tained at a very low temperature to produce fast freezing and aportion adjacent the outlet pipe 33 of the evaporator which produces atemperature sufficient to cool and cause circulation of air in the foodstorage compartment of the re- It is well known to those skilled in theart that the temperature of the air cooling walls of the evaporator issufficiently low to cause moisture within the air in the foodcompartment, upon being chilled or cooled by flowing over theevaporator, to condense on the air cooling walls thereof. This moisturesoon- I mulates on the evaporator walls in the form of a layer of frostor ice. If this layer of frost or ice is permitted to build up oraccumulate beyond a certain thickness it will render the refrigerantliquefying and circulating unit of the refrigerating system inefficientbecause each operating period thereof will be extended over a longerperiod of time than normal to cause the evaporator to produce the properlow temperature in the food compartment. This results in excessive wearon the operating parts of the unit and increases the cost of operatingthe refrigersting apparatus. It is to be understood that this fact hasbeen generally recognized by those skilled in the art and by theirprovision of automaticaliy or semi-automatically operated devices inconjunction with a refrigerating system to cause periodic intervals ofnon-operation of the refrigerant liquefying and circulating unit topermit the temperature of the evaporator to increase above the freezingpoint of water so that the frost or ice accumulated on walls of theevaporator will be melted or so that the air cooling walls will bedefrosted.

According to my invention the brine solution 7 contained in chamber 53below each of the refrigerated shelves 36 and 33 serves as a temperaturehold-over and prevents softening or melting of frozen substancescontained in the trays or receptacles 43 supported on the shelves duringa defrosting period of the air cooling walls of the evaporator. Therefrigerated shelves 33 and 33 and the hold-over chambers 53 aresubstantially isolated or protected from the environment temperaturesurrounding the evaporator by the evaporator walls 21, 23, 23 and 30and, if desired, by a rear and front cover plate or door (npt shown)provided on the evaporator. Therefore the temperature of the air withinthe foods compartment does not materially affect the temperature of theshelves. The brine hold-over solution/in chambers 53, after having beenreduced to the proper low temperature, serves to main-- by absorbingheat therefrom and thereby de-' creases, the maximum load on therefrigerating machine. 7 i v From the foregoing it will become apparentthat I have provided an improved evaporator for refrigerating systemshaving all the desired characteristics of present-day refrigerationrequirements. My improved evaporator providesfor fast form, it is to beunderstood that other forms might be adopted, all coming within thescopeof the claims which follow.

What is claimed is as follows:

1. An evaporator for refrigerating systems comprising in combination,refrigerant conveying. means arranged to define a plurality of walls ofa sharp freezing compartment, a refrigerated shelf disposed horizontallywithin said freezing compartment for supporting a receptacle adapted tocontain a substance to be congealed or frozen, a closed chambercontaining a temperature holdover substance adjacent to and in intimatethermal contact with said shelf, and means for supporting saidrefrigerated'shelf and said chamber in spaced relation to the walls ofsaid freezing compartment. 2. An evaporator for refrigerating systemscomprising in combination, refrigerant conveying means arranged todefine a plurality of walls of a sharp freezing compartment, arefrigerated shelf disposed horizontally within said freezingcompartment for supporting a receptacle adapted to contain a substanceto be congealed or frozen, a closed chamber containing a temperatureholdover substanceadjacent to and in intimate ther-' mal contact withsaid shelf, and means for sunporting said refrigerated shelf and saidchamber in spaced relation to the walls of said freezing compartment,said last named means being of a material separate from and independentof'the walls of said compartment and of the hold-over chamber and shelf.

3. An evaporator for refrigerating systems com-- prising in combination,sheet metal portions having certain parts thereof secured together andcertain other parts thereof spaced apart to provide refrigerant passagestherebetween, said sheet metal portions being arranged to provide aplurality of walls of a freezing compartment, sheet metal portionshaving certain parts thereof secured together and certain other partsthereof spaced apart to provide a refrigerant passage therebetween andarranged horizontally within said freezing compartment to provide ashelf for supporting a receptacle adapted to contain a substance to becongealed or frozen, a sheet metal member secured to said shelf andforming a closed chamber containing a temperature hold-over substance inintimate thermal contact with said shelf.)

and means for supporting said shelf and said chamber from the walls ofsaid freezing compartment, said supporting means comprising a pluralityof members of low heat conductivity and formed of material separate fromand independent of the material of said shelf and -said evaporatorwalls.

' l 4. Anevaporator for refrigerating systems comprising in combination,sheet metal portions hav vide refrigerant passages, therebetween,

v ment.

therebetween andjarranged horizontally within said freezing compartmentto provide a shelf for supporting a receptacle adapted to contain asubstance to be congealed or frozen, 9. sheet metal member secured tothe underside of said shelf spaced apart to provide arefrigerant passageand forming a closed chamber containing a tem:-

perature holdover substance in intimate thermal contact with said shelf,and means for sup- V porting said shelf and said chamber in spacedrelation to the walls of said freezing compart- 5. An evaporator forrefrigerating systems comprising in combination, refrigerant conveyingmeans arranged to define a plurality of walls of a sharp freezingcompartment, means forming a .combined receptacle receiving shelf andclosed container, said combined shelf and container being disposedhorizontally within said freezing compartment and said'container havinga temperature holdover substance therein, and means for supporting saidcombined shelf and container in spaced relation to the walls of saidfreezing compartment. v i

6. An evaporator for refrigerating systems comprising in combination,refrigerant conveying means, arranged to define a plurality of walls ofa sharp freezing compartment, means forming a combined receptaclereceiving refrigerated shelf and temperature holdover element, saidcombined shelf and element being disposed horizontally within saidfreezing compartment, and means for supporting said combined shelf andeleprisingin combination, refrigerant conveying means arranged to definea plurality of walls of a sharp freezing compartment, means forming atemperature holdover element, said element being disposed horizontallywithin said freezing compartment and providing a shelf for the receptionof a receptacle adapted to contain a substance to be congealed orfrozen, and means for supporting said element in spaced relation to thewalls of said freezing compartment.

8. An evaporator for refrigerating systems comprising in combination,refrigerant convey-" EDWARD B. NEWILL-

